diff options
| -rw-r--r-- | source/blender/draw/intern/draw_cache_impl_subdivision.cc | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/source/blender/draw/intern/draw_cache_impl_subdivision.cc b/source/blender/draw/intern/draw_cache_impl_subdivision.cc index 3a5593fa2a5..9241ef67a55 100644 --- a/source/blender/draw/intern/draw_cache_impl_subdivision.cc +++ b/source/blender/draw/intern/draw_cache_impl_subdivision.cc @@ -1095,6 +1095,25 @@ static bool draw_subdiv_build_cache(DRWSubdivCache *cache, cache->resolution = to_mesh_settings.resolution; cache->num_coarse_poly = mesh_eval->totpoly; + /* To avoid floating point precision issues when evaluating patches at patch boundaries, + * ensure that all loops sharing a vertex use the same patch coordinate. This could cause + * the mesh to not be watertight, leading to shadowing artifacts (see T97877). */ + blender::Vector<int> first_loop_index(cache->num_subdiv_verts, -1); + + for (int i = 0; i < cache->num_subdiv_loops; i++) { + const int vertex = cache_building_context.subdiv_loop_subdiv_vert_index[i]; + if (first_loop_index[vertex] != -1) { + continue; + } + first_loop_index[vertex] = i; + } + + for (int i = 0; i < cache->num_subdiv_loops; i++) { + const int vertex = cache_building_context.subdiv_loop_subdiv_vert_index[i]; + cache_building_context.patch_coords[i] = + cache_building_context.patch_coords[first_loop_index[vertex]]; + } + /* Cleanup. */ MEM_SAFE_FREE(cache_building_context.vert_origindex_map); MEM_SAFE_FREE(cache_building_context.edge_origindex_map); |